Automatic cam grinding machine



March 19,1940.

ll-LA. slLvEN Auruurc GAM GRINDING MAGHI'NE I Filed June 2.- 1938 v9v sheets-sheet 1 3ra/ucm HEHBEHTFLEILVEN March 19, 1940.

H. A. SILVEN AUTOMATIC CAM GRINDING MACHINE Filed June 2, 1938 9 Sheets-Sheet 2 igz HERBERT FLSILVEN Mum www v March 19, 19440. f H. A. slm/EN 2,194,434

AUTOMATIC CAM GRINDING MACHINE Filed June 2, 1958 9 Sheets-Sheet 3 HERBERT HEILVEN Sth): nu.

March 19, 1940. H. A. slLvEN AUTOMATIC CAM GRINDING MACHINE Filed June 2, 1938 9 Sheets-Sheet 4 HERBERT HEIM/EN March 19, 1940.

H. A. slLvEN 2,194,434

AUTOMATIC CAM GRINDING MACHINE Filed June 2, 1938 9 Sheets-Sheet 5 HERBERT HEILVEN www W March 19, 1940.` H. A. slLvEN AUTOMATIC CAM GRINDING MACHINE Filed June 2, 1958 9 Sheets-Sheet 6 Fig@I Fig. 7

HERBERT FI.5|| \/EN www@ M March 19, 1940.

H. A. SILVEN AUTOMATIC CAM GRINDING MACHINE Filed June 2. 1938 9 sheets-sheet 7 21u/ucm HEREERTFLElm/EN March 19, 1940.

H. A. slLvEN AUTOMATIC CAM GRINDING MACHINE 9 Sheets-Sheet 8 Filed June 2, 1938 Elma/Mao@ HERBERT FLEILVEN igll.

March 19, .1940. H. A. sxLvEN AUTOMATIC CAM GRINDING MACHINE Filed June 2, 1938 HEHEERTFIEILVEN Patented Mar. 19, 1940 UNITED sfrmssl PATENT OFFICE Herbert A. Silven,'Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application June 2, 1938, Serial No. 211,324

15 Claims.

This invention relates to grinding machines, and more particularly to an automatic camshaft grinding machine.

One object of therinvention is to provide a simple and thoroughly practical machine for automatically grinding a plurality of cam blanks on an'v integral camshaft. A further o-bject .of the invention is to provide an automatic cycle control mechanism for controlling the relative transverse movement of the cam blank v and grinding wheel, and the positioning movement of the Work table to grind successive cam blanks automatically tov a predetermined size and contour. vA lfurther object of Athe invention is to provide an automatic cycle control mechanism in which a main control valve is actuated in timed relation with the lrelativetransverse v feeding movement between the grinding wheel and the camshaft. Another object of the invention is to provide an automatic cam grinding machine in which the rock bar for supporting a camshaft to be ground is rocked transversely relative to the grinding wheel to produce the desired and p redetermined contour on the' Work blank, and in which the path of oscillation of the rock bar is shifted to produce alrelative transverse or grinding feed'between the cam blank and the grinding Wheel. A further vobject of the invention vis to provide an electrically controlled hydraulic mechanism for Acontrolling the main control valve which in turn controls the admission of uid tothe table positioning and the rock bar cylinder.

A further object of the invention is to provide a combined Wheel feeding and pilot valve which serves to shift the main control valve to control thei cycle of operation. Another object of the inventionis to provide an electrically operated mechanism to actuate the pilot valve after a predetermined cycle of operation to mo-ve the various parts ,of the machine into position for `grinding the next cam.. Another object of the invention is to provide a mechanism `for rendering the cycle control mechanism inoperative during the longitudinal traversing movement of the table. Another object of the invention is to provide an automatic cam lgrinding machine with a cycle control'mechanism which is rendered. inoperative .by movement of the main control lever. Other objects will be in part obvious or in part'pointed out hereinafter.

The invention accordingly consists in the feay tures of construction, combinations of elements,

and arrangements of parts, as will Ibe exemplified in the structure to be hereinafter described, and

the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention:

Fig, 1 is a frontelevation of the improved automatic cam grinding machine;

Fig. 2 is a cross sectional view, on an enlarged scale, taken approximately on the line 2 2 of Fig. 1, showing parts of the grinding wheel positioning mechanism in elevation;

Fig. Sis a combined hydraulic piping diagram and electrical wiring diagram; t

Fig. 4 is a fragmentary front elevation of the control apron, on an enlarged scale;

Fig. 5 is a fragmentary cross sectional view through the control mechanism, on an enlarged scale, taken approximately on the line 5-5 of Fig. 1;

Fig. 6 is a horizontal sectional View, on a slightly reduced scale, through the valve mechanism, taken approximately on the line 6 6 of Fig. 5;

Fig. '7 is a fragmentary cross sectional View,

through the rock bar motor, taken approximately f on the line 1--1 of Fig. 1;

' Fig. 8 is a fragmentary perspective view of the rock bar, work 'drive mechanism, and Work feed motor; p

Fig. 9 is a longitudinal sectional View of the feed control or cycle pilot valve; y

Fig. 10 is a longitudinal sectional view of the ymain control valve;

Fig. 11 is a cross sectional view, on an enlarged scale, through the rock bar and the master cam roller indexing mechanism;

Fig. 12 is an end elevation, on an enlarged scale, of the cycle timing mechanism with the cover removed, taken approximately` on the line |2|2 of Fig. 1;

Fig. 13 is a cross sectional View, through the cycle timing mechanism, taken approximately on 'the line" |3--I3 ofk Fig 12;

Fig. .14 is a fragmentary plan view of the rock bar motor shown in Fig. 7; v

Fig. 15 is a fragmentary end elevation of the `master cam roller, the fluid actuating motor therefor, and associated parts;

Fig. 16 is a longitudinal sectional view through the master cam roller and fluid motor, taken approximately on the line l 6--16 of Fig. 15;

Fig. 17 is a cross sectional view through the master cam roller iiuidy motor, taken approximately on the line I1-I1 of Fig. 16; and

Fig. 18 is a cross sectional view through the Work feed adjusting mechanism, taken approximately on the line lS-l8 of Fig. 16.

A cam grinding machine has been illustrated in the drawings having a base 20 which supports a longitudinally movable Work table 2| on the usual flat way 22 and V-way 23. The base 20 also supports a transversely movable wheel slide 25 on the V-way and flat way (not shown) for slide 25. A multi-grooved pulley 29 is mounted on the outer end of a motor armature shaft 3B and is connected by multiple V-belts with a multi-grooved pulley 32 mounted on the outer end of the wheel spindle 26.

The grinding wheel slide 25 is arranged for a transverse movement relative to the base l0 for the purpose of initially setting up the machine for a given grindingoperation and also for the purpose of feeding the wheel transversely prior to automatic dressing or truing of the wheel after a 'grinding operation has been completed. A feeding mechanism of the nut and screw type has been illustrated comprising a feed screw 35 which is vrotatably supported in bearings 35 and 31 which are in turn xedly mounted in portions of the base 2B. A half nut 38 is iixedly mounted on the under side. of the Wheel slide 25 `and meshes with or engages the feed screw 35 so that when the feed screw 35 is rotated, a transverse movement is imparted to the Wheel slide 25 to the half nut 38.

To facilitate manual adjustment of the grinding wheel 21 and wheel slide 25, a manually op erable hand wheel 40 is mounted on the outer end of a hub il which is rotatably supported on a stud 42. The stud 42 is fixedly'supported on a bracket 43 iixedly secured to the base 20. The inner end of the sleeve 4| is provided with a pinion 44 which meshes with a gear 45. The gear d5 is rotatably supported on a stud 46 which is xedly supported on the bracket 43; The gear 45 meshes with a gear 41 mounted on the outer end of a rotatable shaft 48 which is journalled in bea-rings 49 53 and 5| in the base 20. The

inner end of the shaft 48 supports a gear 52- which meshes with a gear 53 mounted on the cuter end of the feed screw shaft 35. It will be readily apparent from the foregoing disclosure that the grinding wheel 21 and the Wheel slide 25 may be adjusted transversely by the manual rotation of the hand feedwheel 4@ to adjust the position of the wheel in setting up the machine for a predetermined grinding operation.

To facilitate automatic adjustment of the wheel so as to advance the wheel automatically for a truing operation, a ratchet wheel 55 is yxedly mounted on the periphery of the sleeve 45. A feed pawl 55 is mounted on a stud 51 which is in turn carriedby an oscillatable pawl carrier 58 which is rotatably-supported on a hub portion of the ratchet wheel 55. The pawl carrler 58 is oscillated automatically by a tableA dog prior to the grinding wheel truing operation in a manner substantially the same as that disclosed inthe prior United States patent to Belden and siiven No. 2,022,178 to which reference may be had for details of disclosure not contained herein.

The longitudinally movable Work table 2 Iv supports a pivotally mounted rock'bar 63 vwhich is supported in bearings` 5l (only one of which has been illustrated in the drawings) on the table Il (Figs. 2 and 8) and is arranged so that it may be rocked about an axis Whichissubstantially. 10

parallel to the axis of the grinding Wheel 2 1. The rock bar 6D is provided With a rotatable head-V stock spindle 62 having a headstock center (not shown). Therock bar also supports a foctstock 63 having a footstock center 34. The headstock center and the footstock center $4 are arranged rotatably to support a camshaft 65 to be ground.

M aster' cams and roller In orderthat the cams kon the camshaft 65 may be ground to a predetermined size and contour, it is.v desirable to providea series of master cams 5G on a master cam spindle 61 which is rosol n tatably supported on the rockbar 60 for con-U- trolling the rocking movement of the rock bar 3U so as to rock the camshaftY 65 being ground transversely toward and from the periphery of the grinding wheel 21 so as to'generate a prede# termined shape or contour thereon. A plurality of master cams 66v are mounted on the master f cam spindle 31 which is` either formed integral with or fixedly secured to the headstock spindle 62 and the headstock center (not shown). The master cams 65, the master cam spindle B1, and

the headstock spindle 62 are preferably arranged as illustrated in Fig. 8 in axial alignment withl the camshaft 65 to be ground. A masterl cam follower roller 68 is slidably androtatably sup- .f

ported on a rotatable shaft 69 which is journalled in suitablebearings sup-ported in fixed relation with the Work table 2|. 'Ihe master cam roller is preferably indexed automatically as the table `2l is indexed longitudinally to position the master cam roller B8 opposite .the master cam 66 which corresponds to the cam being ground on the camshaft $5. The master cam roller indexing mechanism is illustrated in Fig. 11 which will be hereinafter described. VFor a detailed disclosure of the automatic shifting of the master cam roller, reference may be had to the priorl United States PatentNo. 1,783,755 to Trefethen and Belden dated December 2, 1930, and Aalso `to the UnitedStates Patent No. 2,022,178 to Belden and Silven dated November 26. 1935.

Rock bar actuating mechanism is pivotally connected to a block 13 fixedly mount'-v y ed on the right-hand end of a rod 14 by means of a tapered pin 15. The rod 14 is slidably keyed to a vhollow tubular member 16 by a key ,11. A spring 18 surrounds the rod 14 and is-interposed between an integraly flange 19 formed'on the rod 14 and a slidable sleeve 31'! which is slidably mounted on the .rod 14. A spring 8l surrounds the other end of the rod 14 and is interposed between the sleeve 8i) and an adjustable collar 82` which is screw threaded into athreaded portion '1d lture 84 in the plate 82.

83 within the hollow tubular member 16. The

compression springs'l and 8| serve to exert a.

1 rection (Fig. 7) so as to maintain the master cam roller 66 in operative engagement with the master cam roller 68 during a grinding operation. A single spring might be employed instead of the two spaced springs 18, and 8|, if desired, and interposed between the ange 19 and the adjustablestop plate 82, in which case the slidable sleeve 89' may be dispensed with.

By adjusting the position of the stop platel or collar 82 within the screw threaded portion 83, the v.springs 18 and 8| may be compressed so as to exert lthe desired predetermined pressure between the master cam 66 and the master cam roller 68. l

To facilitate adjustment of the compression of the' plate 82 readily to adjust the compression of the springs 18 and 8|, the plate 82 is provided with a central aperture 84 which is preferably square or rectangular in shape. A rod 86 has a squared-oill end which slidably engages the aper- 'I'he rod 86 is carried by a hollow cup-shaped member 88 which is rotatably sup-ported'by a plate 89 which forms a circular slideway to engage a flange 9D projecting f from the edge of the cup-shaped member 88so `that the cup-shaped member 88 may be readily locking the cup 88 in adjusted position after` the compression of the springs '|8 and 8| has been adjusted to the desired extent.

Hydraulic actuation-Rock bar A uid pressure mechanism is provided to rock the bar 6!) to an inoperative position automatically before the table 2| is traversed or indexed, so that the master cam 66 and follower 68 and product camshaft and grinding wheel 21, respectively,l are separated before the table 2| starts its traversing or indexing movement. This mechanism may comprise a fluid pressure cylinder 96 having a piston 9| slidably mounted therein. The piston 9| is preferably formed as illustrated as an integral projecting flange ofthe tubular member'16 which is slidably keyed to the rod 'I4 whichv in turn is pivotally connected to a stud 12 to move the 'rock bar. When fluid under pressure is admitted through a pipe 92 into a cylinder chamber 93 within the cylinder 90, 'the piston 8| moves toward the left (Fig. 7), carrying with it the tubular member '16, the adjustable thrust plate 82 and, through the springs 8| and '19, serves to causean endwisemovement of the rod 14 which operates through the pivotally supported block 72 to rook the rock bar 60 in a counter-clockwise direction (Fig. '7) so as to separate the master'cam 66 from the master cam roller 68. During this movement of the rock bar, fluid within the cylinder chamber 94 is exhausted through a'pipe 95. The valve mechanism for controlling the admission of uid to the cylinder 9D will be described hereinafter.

t An adjustable stop collar 96 is screw threaded onto the periphery of the block 'i3 and is arranged to engage the `end surface 91 of4 the cylinder 98 to serve as a stop to limit theA movement of the piston 9| toward the left (Fig. 7) and also to limit the rocking and separating movement of the rock bar 6|);r A lock collar 98 serves to facilitate lockedly supported relative to the table 2|.

ing the stop collar 96 in the desired adjusted position. In order to permit a free movement of the cylinder 99 during the rocking movement of the bar 60, the cylinder 96 is provided with diametrically opposed trunnionsl and y| which are supported in bearings lill and |02, respectively, within the headstock frame which is x- The entire headstock end of the table is provided with a casing |03 which encloses the entire mechanism to prevent grit and other foreign matter. from getting within the operating parts. In order to facilitate adjustment of the rock bar `springs '|8 and 8|, a cover plate |94 is hinged to the front of the casing H03 and is arranged so that the cupshaped member 88 may be rotated to adjust the springs as desired. v

The work supporting table 2| is moved longitudinally relative to the base 2li by means of-a fluid pressure operated mechanism comprising acylinder il@ which isiixed to the under side of the table 2|. slidably supported within the cylinder lill.

The pistons and H2 are each mounted on the inner ends of a pair of piston rods ||3 and IM, respectively, which are inl turn fixedly con nected at their outer ends by hollow brackets 5 and H6, respectively. The brackets ||5 and H6 serve to anchor the'outer ends of the piston `rods relative to the base 28. In order to permit expansion of the parts, the length of the piston rods ||3 and |84 is such that the pistons and H2 are spaced from `each other by van amount suiicient to take care of expansion of the parts during the normal operation of the machine. The admission of uid under pressure to either a` 'cylinder chamber or i8 through a pipe H9 or |20, respectively, is controlled by a table controlling or reversing valve |2i.

Table control valve The table control valve |2| is preferably a piston type valve comprising va valve stem |22 having formed integral therewith valve pistons |23, |24, |25. and |26. Fluid under pressure from a source to be hereinafter described passes through a pipe |27, into a valve chamber |28 located between the Valve pistons |24 and |25, and in the position of the valve illustrated in Fig. 3, passes through the pipe |28 into the table cylinder chamber I8 to cause the table`2| and cylinder H0 to move toward the right. During this traversing or indexing movement of the table 2|, iluid is exhausted from the cylinder chamber through the hollow piston rod H3, the bracket I5, pipe H9, into a valve chamber |29 in the table control Valve l2|, and out through an exhaust pipe |39. The connection of the table control valve with the other operating parts of the iuid pressure system will be hereinafter described.

wom rotation As above described, the headstock spindleBZ,

the master cam spindle 6l, and the camshaft 65 are arranged in axial alignment with each other and the camshaft 65 to be ground is provided with a driving dog |33 which serves to connect the camshaft 65 so as to rotate with the headstock spindle 62 and the master camshaft 61; The master cam spindle 6l and the headstock spindle 62 are driven by a inotordriven driving mechanism contained within the headstock casing |83 (Fig. 3). This mechanism comprises an electric motor |34 (Fig. 8) havinga motor shaft |35 which carries a worm |36; The worm |36 A pair of pistons and l i2 are meshes with a worm gear |31 mounted on one end4 of a shaft S38 which is preferably arranged parallel to the axis of oscillation of the rock bar` y the headstock casing |03 on the table 2|.

It will be readily apparent from the foregoing isclosure that when the electric motor |34 is set in. rotation, a rotary motion will be transmitted through the shaft |35, the Worm |36, the worm gear |31, the shaft |33, the pulley |39, the V- belts |40, the pulley liti, the shaft 1&2, the sprocket m3, the link chain IM, and the sprocket |45 to rotate the master cam spindle Sii which in turn transmits a rotary motion to the master cams 66 and the camshaft |35 to be ground. Due to the fact that the master cam E6 is maintained in yielding engagement .with the master cam roller |58 by means of the springs 18 and 8| above described, when the master cams (i5 are rotated, a rocking motion will be transmitted to the rock bar 6B, which serves to oscillate the camshaft da toward and from the peripheral grinding surface of the grinding wheel 21 to grind and generate a predetermined contour on the cam being ground.

Master cam 'roller indexing mechanismy The master cam roller 68 is preferably indexed longitudinally automatically in timed relation with the indexing movement of the table 2i so ber 26, 1935, to which reference may be had forl details of disclosure not found herein. The base 2Q is provided with a dog bar |5|l (Fig. 1l) having a plurality of adjustably positioned dogs |55 which are arranged in spaced relation with each other and spaced in accordance with the spacing of the cams on the camshaft 65 to be ground. A star4 wheel |52 is mounted at the lower end of a vertically positioned rotatable shaft |53 which is journalled in a housing |515 carried by the headstock bracket |55 which is rigidly secured to the table 2| The upper end of the shaft |53 carries a gear |56 which meshes with a gear (not shown) mounted on the lower end of a rotatable shaft |51. A gear |58 is mounted on the upper end of the shaft |51 and meshes with a rack bar |59 which is iixedly mounted on a non-rotatable slidably mounted shaft |60. The shaft Hifi carries a yoked member 16| (Figs. 1l and 16) which is arranged to engage a flange |62 which is formed integral with a slidably mounted sleeve |63 which is slidably supported on the shaft 69. The sleeve |63 supports an anti-friction bearing |515 which in turn rotatably supports the master cam follower roller. It will be readily apparent from the foregoing disclosure that when the table 2| is traversed or indexed longitudinally to position suc- 1 cessive cams on the camshaft 55| to be ground in operative relation with the grindingwheel 21, a

corresponding indexing movement will be imparted to the master cam follower roller 6B automatically to position it in operative relation with the master cams @6 opposite to the master cam 65 which corresponds with the product cam o the shaft 65, to be ground.

` Grinding feed In order to attain one object of this invention, l

it is desirable to impart. a relative approaching and receding movement'between the camshaft to" bar, being a lighter element, may be more readily and accurately fed and controlled, especially in av comparatively fast cycle of operation, than a.

heavy massive grinding wheel slide.. A feeding mechanism is, therefore, provided whereby the arcuof oscillation of the rock bar is shifted as the grinding proceeds to produce the desired grinding f feed and thereby sizing of the cam being ground.

This feeding movement is preferably accom-Vv plished by bodily moving the master cam follower roller 68 to cause the work axis graduallyto approach the wheel axis and thereby to grind the cam blank on the shaft 65 to the requiredsize. As illustrated in the drawings, the master cam roller shaft 69 is provided at its opposite ends with eccentric trunnion lportions I1@ (Fig. 16) only one of which has been illustrated in the drawings. The trunnion portions r|19 are mounted in suitable bearings |1| which are xedly mounted on the frame of the headstock within the casing H33. In order to obtain `the desired feeding movement, thetrunnions |1 are rocked about their axis which rocks thefeccen- Aso.'

tric shaft 69 and thereby produces an eccentric feeding movement to the master cam follower roller 68.

A hydraulic actuating mechanism isv provided for controlling the oscillation of the trunnions |113 to rock the eccentric shaft ,69 which comprises a single-vane type fluid motor |12 having a fluid chamber |13. A single vane i111 is iixedly pressure is admitted through a passage .11d and a port |11 into the kmotor chamber |18` tocause `mounted on a motor shaft |15. Fluid under y the vane to rotate in a counterclockwise direction (Figs. 3 and 17) to produce the desired infeeding movement'of the camshaft 65 to grind i 601 into the motor chamber |18 to move the-vanev |14 in a counterclockwise direction v(Figs. 3 andv 17) the uid within thek chamber formed at the other side of the vane |14 serves to close a ball` check valve 119 and thereafter to cause fluid within said chamber to exhaust through a passage |86 and an'adjustable needle valve iti andV Similarly, when the` through va passage |82. duid under pressure to the feed motor |12 is reversed, fluid enters through thev passage |852,

' 'I'he fluid motor |12 is operatively connected to oscillate or rock the shaft |10 to produce the desired Lfeeding movement. It is desirable to provide a suitable adjusting mechanism between the uid motor I 12 and the shaft |10 so that the extent of rocking movement of the shaft |10 and the eccentric master cam roller supporting shaft 69 may be precisely adjusted so as to regulate the' extent of the infeeding movement. A cam |85 is fixedlymounted on the end of the motor shaft |15. The cam |85 is engaged by a follower roller |86 carried by an oscillatable member E81 which is pivotally supported on a stud |88. The roller |86 is maintained in operative contact with the camv |85 by means of a spring |89. A rock arm |90 isv xedly mounted on the end of the shaft |10 and is normally urged in a counterclockwise direction by means of aspring |9| so that its under plane surface |92 engages an adjustable roller |93 carried by the oscillatable membery |81. 'I'he roller |93 iscarried by a stud |94 which is supported on a slide block |95. The slide block |95 may be adjusted longitudinally along a slideway |96 by means of a rotatable screw |91 which is supported by and is held against endwise movement in a bearingv |98 and is screw threaded through an aperture in the slide |95. By varying the position of the roller |93 along its slide surface |96, the extent of feeding movement transmitted by the motor |12 may be varied, .as desired. For each infeeding operation, the vane |14 of motor |12 revolves one half turn with the shaft |15.

`It will be readily apparent from the foregoing construction that by adjusting the position of the slide |95 along its slideway |96, the lever arm between `the point of contact of the roller |93,

' the surface |92 and the axis of the pivot stud |88 'will be varied, thus varying the amount' of motion transmitted by the oscillatable member |81 to rock the shaft |10 so as to produce the desired infeeding movement between the camshaft and grinding wheel 21. It should be noted that the surface |92 is a plane surface which is positioned when roller |86 is in engagement with the concentric portion of the cam |85 so that it coincides with the axis of the stud |88. If the roller |93 is adjusted longitudinally so that its line of contact with the surface |92 coincides with the axis of the stud |88, no rocking motion will be transmitted to the'lever |90 and consequently no feed Will be imparted to the master cam roller. If the roller |93 is adjusted toward the right away from the axis of the stud |88, then the rocking motion of the shaft |10 and of the roller 68 will be increased. By manipulation of the screw |91 to position the roller |93, a predetermined amount of feeding movement may be obtained to grind the cam blanks on they camshaft 65 to the desired size. By manipulation of the needle valve |8|, the rate of infeed may be adjusted as desired. It should be noted that the vane |14 of the motor 12 makes one-half a revolution for Aeach infeeding movement. To

facilitate adjustment of the roller |93, an index point is provided on the slide |95 and a graduated scale is provided adjacent to the edge of the slideway |96 so that the roller |93 may be readily set at the required distance from the stud |88 to v u produce the desired infeeding movement.

The slide |95 is preferably slotted, asindicated' in Figs. 1`5 and 18,- and a push and pull screw is provided between the spaced portions thereof adjacentvto'the slot to facilitate locking the slide |95 in'adjus'ted postition relative to the screw |91. l

Cycle pilot feed control valve The admission and exhaust of fluid to and from the feed motor |12 is controlled by a feed control or cycle pilot valve 200. This valve is preferably of a pistony type comprising a valvev stem having yformed integral therewith a plurality of Valve pistons 202, 203, 204, and 205. A fluid pressure system is provided for conveying fluid under pressure to the various mechal nisms of the machine and comprises a reservoir or sump 206. A motor driven fluid pressure pump 201 pumps fluid through a pipe 208 from the reservoir 206 and forces it through a pipe 209,r a pipeA 2|0, into a'valve chamber 2|| located between the valve pistons 203 and 204 of the valve 200. In the 'position of the valve illustrated in Fig. 3, fluid under pressure passes from the valve chamber 2| l, through a pipe 2|2, the pas--l sage |16 and the port |11, to cause the vane |14 of the feedvmotor |12 tol move in a counterclockwise direction (Figs. 3 and 1,7)4 to cause an infeeding movement of the camshaft 65. During this movement, fluid under pressure exhausts from the chamber on the opposite side of the vane' |14, out through the adjustable `needle valve |8| which regulates the speed of movement thereof, and out through the passage |82 and a pipe 2|3, into a valve chamber 2 I4 located between the valve pistons 204 and 205 of the.l feed controlcycle fpilot valve 200 which exhausts through pipe 215 into the reservoir 206.

Similarly, when the valve stem 20| is moved toward the right (Fig. 3), the passage of fluid under pressure to and from the motor |12 is reversed'so as to passiiuid under pressure through the pipe`2|3 and passage |82 to cause the vane |14 of the motor |12 to move in a clockwise direction (Figs. 3 and 17) to separate the cam being ground from the grinding wheel 21. f A spring 2|6 serves normallyto hold the Valve stem 20| in its extreme right-hand position (Fig. 3),` and a solenoid 211 which is connected to the left-hand end (Fig. 3) of the valve stem 20|' serves when energized to shift the valve stem. 20| to its extreme left-hand position so as to produce an infeeding movement. The electrical control for the solenoid 2|1 will be hereinafter described.

The feed control or cycle pilot valve 200 also serves to control the admission to and exhaust of fluid from the rock bar cylinder 98. The pipe 2|2 (Fig. 3) is connected with the pipe 95 to pass fluid under pressure to the cylinder vchamber 94 so as to rock the ba`r-60 and maintain the master cam, 66 in operative engagement with the master cam roller 68 when fluid is admitted through the pipe 2|2 to start an infeeding movement of the work toward the grinding wheel face.

M ain control valve Similarly, when the feed control cycle pilot valve shifts to its reverse position, fluid under pressure passes through the pipe 228 into the cylinder chamber 221 to shift the main control valve 223' to its extreme left-hand position. The functions of the main control valve will be herein--r after described.

Pilot valve A pilot valve 233- is provided for the purpose of automatically shifting the reverse or table control valve l2 i. The pilot valve 233 is a piston type valve `comprising the Valve stem 23| having formed integrally therewith a plurality of valve pistons 232, 233, 234 and 235. The valve stem 23| is normallyV held in a central position by means of a spring 236.. The outer end of the valve stem 236 is provided with a spool-shaped member 238' which is arranged to be actuated by a stud 239 carried by a lever 24|). The lever 240 is supported on a rock shaft 24| which supports at its other end a pilot valve actuating lever 242 which is actuated by dogs on the table, as will hereinafter be described.

Fluid under pressure from the valve chamber |23 in the table control valve |2| passes through a pipe 243 into a valve chamber 244 located between the valve pistons 233 and 234. In the position of thevalve as illustrated in Fig. 3, the pressure balances against the pistons 233 and 234'. When a table dog engages the lever 242 to rock it in a clockwise direction so as to shift the valve stem 23| toward the left (Fig. 3), liuld under pressure within the chamber 244 passes out through a pipe 245, into a valve chamber 246 formed in the left-hand end of the table control valve l2 and serves to shift the valve I2| toward the right into its reverse position. During this movement, fluid within the valve chamber241 in the opposite end ofthe reverse or table control valve |2|, passes through a pipe 248 into a valve chamber located between the valve pistons 234 and 235 and exhausts through a pipe 250 into the reservoir. Similarly, when the lever 242 is rocked in a counterclockwise direction (Fig. 3), the valve stem 23| is moved toward the right and fluid under pressure from the valve chamber Y 2,34 passes through the pipe 248 in the valve chamber 241 to shift the table control valve |2| toward the left in a reverse position.

Table indexing movement The table 2| is traversed or indexed longitudinally and automatically by means of a fluid pressure mechanism, above described, which comprises a cylinder H0 containing pistons HI and H2 which are connected by means of the hollow piston rods l |'3 and I4, respectively, with hollow brackets l |5 and I6, respectively, on the base 2U. The admission of fluid to either cylinder chamber H1' or H8 is controlled by the table controlling a reversing Valve |2l. Fluid under pressure from the pump 261 passes through the pipe 209, a pipe 252, into a valve chamber 253 located between the valve piston 222 and 223 in the main control Valve 22 0, and through a pipe 254, into the valve consequently no fluid can flow to the table control valves or to the table cylinder duri-ng the infeeding movement of the workr support. j

Wheel tru/ing mechanismy is preferably ytrued automatically in between operations, that is after one camshaft has been. ground and before the new shaft is ground upon, so that a trued grinding wheel face will be presented at the start of each grinding oper-I N ation.

A truing apparatus comprising a bracket 258 is xedly mounted on the table 2| and carries a truing tool which may be adjusted relative to the bracket 258 by means of a micrometer adjusting screw 253.

The details of the ytruing K mechanism have not been illustrated, since this.

zo. .y

feature is not considered to be part of the present invention. For further details of this mech?.

anism, reference may be had to the prior United States patent to Belden and lSilven No. 2,022,178 f dated November 26, 1935. 'I'he truingmechanism in the present case is substantiallyr` as,4 v 30.1`

shown in the prior patent except that it is arranged directly below the footstoc-k center 64. instead of above the center. The diamo-nd or truing tool, however, is held in ya rigid fixed position and is arranged to true the grinding.

wheel when it is in its rearmost position. In the present invention, the grinding wheel 21 is not moved toward the work piece for a feeding move-k ment but it held in a 'relatively fixed position n and is adjusted only yto compensate for wheel wear and truing. After the last cam on the camshaft has been ground, the feed motorA |12 causesv the work. to recede from the grinding wheel 21. The table 2| is then given an addi` tio-nal traversing movement to carry the pre.

viously adjusted diamond truing tool across-the operative face of the grinding wheel totrue the same.

Slow travense--Truz'ng The normal traversing or indexing `movement of the table is comparatively rapid to2r reduce the loss of time between successive Lgrinding operations. The normal speed is not at all' suited for a truing operation which requires` a very slow, uniform relative traversing movementbe-l l tween the truing tool and the grinding wheel.

To obtain a slow truing traversing movementof'.

the table, a slow speed valve 263 is provided through which fluid exhausting from the table cylinder HD passes. When fluid isr exhausted. from the cylinder I3 through either the pipe H 9 or |20, it passes through either the valve chainber |23 or a valve chamber 231, respectively, and from there through a slow speed control valvey 263, into the reservoir 266. The slow speed valve 263 is a piston-type valve comprising a valvel stem 26| having formed integrally therewith valve pistons 262, 263, 264, 265- and ,266. The. outer end of the valve stem 26| provided with a spool-shaped member. 261 which is engaged. by a stud 268 carried by the lower end of a rock arm 263 which is in turn supported on a..

rock shaft 210. The rock shaft-21|l is journalled in a suitable bearing 21| which i'sxedly mounted relative to the base 2,0. The rock shaft 210 projects from vthe'front` ofthe machine.r base and 'Iiiy In a machine of this type, the grinding. wheel 10"' carries on its outer end. a rock arm 212 having a roller 213 mounted at its upper end. The roller 213 is rotatably supported on a stud 214'. The roller 213 is arranged in the` path of a cam surface 215 on a truing dog 216 which will be hereinafter described. When the table 2| is traversed toward the left (Figs. l, 3 and 4) after grinding-the last cam on the camshaft to be ground, the cam surface 215 oi the truing dog 216 engages'the roller 213 and rocks the arm 212, the rock shaft 210, and the arm 269 in a counterclockwise direction (Fig. 4) which serves to move the valve stem 26| of the slow speed valve 260 toward the right (Fig. 3). v Similarly, when the table traverses in the opposite: direction and when the cam 215 moves toward the right and leaves the'roller 213, the arm 212, the rock shaft 210 and lever 269 are rocked in a clockwise direction (Figs. 3 and 4). A spring 211 within the valve A260 aids in shifting the valve 260 toward the left (Fig. 3) and thereby allows the table 2| again to be traversed at its normal indexing or traversing speed. vFluid exhausting from the table cylinder H0 through the pipe ||9 and valve chamber |20 normally passes out through the pipe |30 into `a valve chamber 200 and passes out through afpipe 28| and a pipe 282 t0 the reservoir 206. In the position orf-the valve as shown in Fig. 3, the ports are wide open so that fluid may iiow unrestricted from the pipe |36, through the pipes 28| and 282, into the reservoir 206. When the table moves into a truing position, the valve stem 26| is moved toward the right (Fig. 3) against the compression of the spring 211 so that the valve piston 265 closes the port atthe end of the vpipe |30, after which fluid from the pipe |30 exhausts through an adjustable needle valve 263 and a pipe 284 which connects with the pipe 282 to return the fluid to the reservoir 206. By manipulation of the valve 283, the desired truing speed or' the table 2|, in its traverse towards the right, maybe obtained.

Similarly, when the table control valve |2| shifts to reverse the direction of travel of the table and start it moving toward the left, during the truing operation, fluid within the'chamber |8 of the table cylinder 4| I6 will exhaust through pipe |20 into the valve chamber 281 located betweenr the valve pistons |23y and |24 and passes out through a pipe 288 and a pipe 289, into a valve chamber 290 in the slow speed valve 260 located between the valve pistons 262 and 263 and through a pipe 29| which connects with the pipe 282 to return the fluid to the reservoir 206. In the position of the slow speed valve 260 (Fig. 3), unrestricted passage of iiuid is permitted through the valve chamber 290. When the valve 260 is in a truingposition, however, the port at the end of the pipe 289 is closed by the valve piston 262, after which fluid exhausting through the pipe 288 passes through an adjustable needle valve 292 into the pipe 282 and returns to the reservoir 206. By manipulation of the needle valve 292, the truing speed of the table and truing tool in the reverse direction (toward the left) may be varied as desired.v By manipulation of the adjustable needle valves 283 and 292, the truing speed of the table may be adjusted inits movement in either direction so that the table travels either at the same or different speeds when moved in opposite directions.

In order to obtain the maximum production, the table 2| must be traversed at'a rapid rate of speed during rits idle return strokey and also is fixed to the truing dog 216.

at a fast indexingrspeed during the grinding stroke of the table. `An adjustable stop screw 26|a serves to adjust the left-hand end position of the valve 260. By manipulation of the screw movements. By adjusting the screw 26|a to vary the aperture of the port at the end of the pipe |30, the indexing speed may `be increased or decreased to obtain the desired results.

Truz'ng dog It is desirable that the speed of movement of the table 2| be. slowed down gradually to a truing speed to prevent shocks and vibrations which would occur with a sudden change of speed. To accomplish this result, the truing dog 216 is provided with a pivotally mounted ,latch block 293 which is pivotally supported ona stud 294 which The swinging movement of the block 293 yin a counterclockwise direction is limited lby an adjustably positioned stop 295. When the table 2| is moving toward the left into a truing, position, the roller 213 engages a surface 266 before the roller contacts with the cam 215 to rock the lever 212 and thereby shift the slow speed valve to slow down the table Amovement a short distance before the diamond or truing tool engages the wheel so as to prevent any shock or vibration of the table as the truing operation starts. The truing operation continues until an adjustable dog 291 v It may be desirable at times during the operation of the machine to render the truing mechanism inoperative so that several camshafts might be ground without automatically truing` the wheel between shafts. To accomplish this result, a dog 2&6 is pivotally supported by a stud 226 on the truing dog 216. The position. of the dog 238 is governed by a stop screw 406 which serves adjustably to position the dog 206 relative vto the truing dog 216 so that it may be positioned in the path of or out of the path of the lever 242; A spring 461 serves to hold the pivotally mounted dog 293 in position against the stop screwy 406. `In the position of the parts as shown in Fig. 4, the dog 29B is shown out of the path of the lever 222 so that after the last cam on the shaft has been ground, the table will be moved beyond the last cam on the shaft and the wheel will be automatically trued. In case it is desired to stop the machine without truing the grinding wheel after a camshaft has been ground, the stop screw d66 is adjusted to lower the dog 298 so that the dog will engage the lever 242 when the table moves toward the left and reverse the table movement without permitting the truing tool toy engage and true the wheel.

Also, if it is desired, in setting up the machine with a new grinding wheel, totrue a considerable amount of material oil the wheel, the tab-le may be moved into a truing position so that the upper end of the lever 232 is positioned between the dogs 23?' and 233 at which time the dog 238 may be depressed so that the table will be continuously reciprocated'as governed by the dogs 29! land 233 until the desired amount has been trued off the periphery of the Wheel, after', which thestop screw 403 may be adjusted to raise the dog 238 and allow the table to traverse. toward Cycle control mechanism In order to attain one of the objects of this invention andA to obtain the maximum efliciency from the machine, a cycle control device is provided which serves, after 'a cam has been rotated through a predetermined number of rotations in operative grinding engagement with the grinding wheel 2, to actuate the cycle pilot or eed control valve 233 which in turn serves to actuate the main control Valve and thereby to admit iiuid under pressure to the rock bar cylinder 30 to rock the master cam out of engagement with the follower 53 and thereby separate the cam blank being ground from the grinding wheel 2 to admit fluid to the feed motor 72 to shift the position of the master cam roller 38, and then to admit fluid under pressure to the table traversing cylinder H automatically to index the table 2| to present the next cam blank on the camshaft S to be ground into operative relation withA the grinding wheel 2l. This is preferably accomplished by means of a cycle control or counting device 333 which is contained within a casing located on the right-hand end of the headstock casing |03 (Fig. l).

The counting device 300 comp-rises a ratchet wheel which is keyed to a rotatable shaft 302. A pawl 383 is carried by a stud 306 on a bracket 335 which is adjustably mounted on the upper end of an arm 333. The arm 306 is adjustably mounted on a bracket 33T which is rigidly clamped on the dovetailed portion Ti of the rock bar 60. hold the pawl 333 in an operative position against a stop 3300i on the bracket 335. It will be readily apparent from the foregoing disclosure that each time the rock bar 00 is oscillated, the pawl 303 will be oscillated thereby. The arm 363 upon which the pawl 303 is carried has a portion which is substantially concentric with the axisof the rock bar so that the bracket 355 may be adjusted along the arm 303 without changing the relative position of the ratchet and pawl. It will be readily apparent that when the rock bar 60 is oscillated in a clockwise direction, the pawl 303 rides idly over' the teeth of the ratchet wheel 30| and similarly, when the bar 60 oscillates in a counterclockwise direction, the pawl 333 engaging teeth on the ratchet wheel 353| will cause the ratchet wheel 30! to rotate a partial turn. The extent of movement of the ratchet` wheel 30| or the number of teeth picked by the pawl 333 depends upon the adjustment of the bracket 335 on` the arm 306. When the arm 335 rocks in a counterclockwise direction (Fig. l2), the pawl 303 on its downward movement swings out of engagement with the ratchet wheel and on its upward movement swings into engagement and rides idly over one or more teeth of the ratchet Wheel 30| which are picked to rotate the ratchet wheel 33| on A spring 303 serves normally to the next stroke thereof. A holding pawl 303 -is pivotally mounted on a stud 3 0 supported by the casing 300. A tension spring 3| is connected between the upper end of the holding pawl 303 and a stud fixed to the. casing 303 and serves normally to hold the holding pawl 333 in engagement with the ratchet wheel 30 The ratchet Wheel 30| is provided with an integral sleeve 3|2 which rotatablysupports a cam 3|3. The cam SH3 is arranged to engage an actuating roller 3M of a normally closed limit switch 3|5. going disclosure that each time the rock bar 30 is rocked or oscillated by the master cam 38 and the follower roller 38, the pawl 333 will pick a predeterminednumber of teeth on the ratchet t will be readily apparent from the forerock bar 60 represents one complete rotation of I the master cam and the product being ground; After a predetermined number of rotations of the camshaft 63 or master cam 68 or oscillationsv or" the rock bar 60, the pawl 303 and ratchet wheel 30| willrotate the cam 313 asuiiicient dis-` tance to actuate the limit switch 3|3 and break' a circuit, thereby deenergizing the solenoid 2H which releases the compression of the spring y2||i to shift the feed control-cycle pilot Valve'230,

and cause a separating movement between the camshaft and the wheel 2li due to the operation of the vane type feed motor |12.

zo y

The cam 3|3 is provided with an integral sleeve having a flangedportion 3|0.' The sleeve closely`v ts on the sleeve 3|2 and is split at one side by a saw cut 3|? and is arranged to be clamped in adjusted position on the sleeve 3|2 by means of a screw 3|8. A knob 3|9 is ixedly pinned to the end of the shaft 302. The knob 3M)y is provided with a flanged portion 320 which is graduated and serves with a zero point on the hanged member 3|6 to facilitate adjustment of the cam member 3|3 relative to the pawl and ratchet mechanism.

It is desirable to provide a suitable mechanism for automatically returning the counting mechanism 300 to its initial positionwhen the hold-v ing pawl 309 is withdrawn from the ratchet Wheel 30| after a grinding cycle'has been completed.

A helical spring 32| surrounds an integral hub` v portion 322 of the casing 336. One end oi the spring 32| is fastened to the hub portion 322 by i means of a screw 323. The other lend of the spring 32| is xedly secured to a hanged member 324 formed vintegral with the shaft l332 by means of a screw 325. The spring 32| is arranged so that when thepawl 333 and ratchet wheel 30| incrementally index the cam 3|3, the

spring 32| will beA gradually wound up so that after a cam blank has been ground and the holding pawl 309 withdrawn from the ratchet ,wheel 30|, the released tension of the spring 32| automatically turns the shaft 302, the' cam 3| 3,and the ratchet .wheel 30| in a reverse direction to its kinitial position ready for the next grinding reverse the feed rmotor and automatically to control the valve mechanisms of the machine so as to index or traverse the work table to position `the next cam to be ground in operative relation with the l grinding wheel. y

' The actuation of the holding pawl 303 is preferably automatically controlled in timed relation with the other mechanisms of the machine. A fluid pressure operated cylinder 328 is xedly mounted relative to the casing 300. A piston 329` is slidably mounted within the cylinder 328 and is provided with a piston rod 330 which is connected to actuate the holding pawl in a counterclockwise direction .to move it to an inoperative position. A spring 33| within the cylinder 328 normally `holds the piston in itsl left-hand position (Fig. l2) to hold the pawl 303 out of engagement with the ratchet wheel. When fluid under pressure is admitted to the cylinder chamber 332, as will be hereinafter described, the piston 329 and piston rod 330 are moved toward the right and the released ,tension of the spring 3|| serves to rock the holding pawl 309 in a clockwise direction to engage the ratchet wheel The timing or counting mechanism is automatically reset. When the `fluid within the cylinder chamber 332 is exhausted, the released compression of the spring 33| serves to dischgage the holding pawl 309 and the released tension of the spring 32| returns the counting mechanism to its initial position. This mechanism is preferably automatically controlled in timed relation with the control leverfmechanism.

Control Zeverv mechanism adjusted, the machine vgrinds successive cams on a camshaft from the footstock end of the table toward the headstock, that is, while the table 2| is intermittently indexed toward the right.

' When the table reaches the extreme right-hand position, the table. control or reverse valve |2| is shifted into a reverse position so as to admit fluid under pressure through the pipe ||9 rapidly to traverse the table toward the left to return it to its initial starting position.

The intermittent traversing of the table is accomplished by opening the table control or reverse valve |2| by moving the valve into the position shown ,in Fig. 3, whereupon the table is traversed untila lever is engaged to shiftthe valve 2| to a central position to cut off fluid under pressure from both ends of the table cylinder, thereby stopping the table in position to grind the next cam blank on thefcamshaft 65. An actuating mechanism is provided for the valve f |2| so that movement of the table 2| operates to close the valve |2| so that when the table is traversed through a predetermined distance to position the next cam on the camshaft 65 being ground in operative relation with the grinding wheel 21, the valve |2| is automatically shifted to a central or neutral position to stop the ilow of fluid under pressure to either end of the table cylinder ,||0. This is preferably accomplished by means of a dog bar 330:1, which is adjustably mounted on the front edge of the table 2| by -parallel with the table movement.

means of bolts and a T-slot (Fig. 5). The dog bar 33041, is provided with elongated slots 33|a (Fig. 4) which serve adjustably to support a plurality of adjustable dogs 332a. The` dogs 332a may be adjusted along the bar to conform with the spacing of the cams on the camshaft 65 to be ground. `The dog bar, if necessary for any variation in successive camshafts, may be adjusted longitudinally of the table without upsetting the adjustment of the individual dogs.

The valve |2| is provided with a valve stem |22 which is operatively connected to a manually operable control lever 333 which is supported on the forward end of a rock shaft 334. In the pre ferred form, the lever 333 is pivotally supported on a stud 335 which is carried by a short lever 336 which is rigidly secured to the front end of the rock shaft 334. 'Ihe inner end of the rock shaft 334 carries xedly mounted thereon a downwardly extending lever 331 which is provided with a follower member 338 which in turn engages a groove in a spool-shaped member 339 mounted on the end of the valve stem |22, so that by manually rocking the lever 333, thetable control valve |2| may bereadily shifted to change the direction of movement of the table 2|. In order that the control lever 333 may be moved in the direction of table movement, a second actuating lever is provided for cooperating with the table dogs. As illustrated in the drawings, a dog lever 340 is provided with a forwardly project-` ing pin or stud 342 which rides in a rectangularly shaped aperture 343 within the short lever 336. The extent of movement of the lever 340, without transmitting motion to the main control lever 333, is controlled by the adjustment of a pairof spaced opposed screws 344 and 345 which are ar` ranged on opposite sides of the rectangularly shaped aperture 343.

The lower end of the lever 331 is providedwith a cam plate having a portion 346 which is sub1# stantially concentricv with the axis of the rock shaft 334 and an angularly arranged cam surface 341 arranged at approximately A roller'348 carried by a spring-'pressed plunger 349 serves normally to hold the lever 331 in its extreme left-hand position, that is, with the table con.- trol valve |2| in the position illustrated in Fig. 3.

Assuming the table 2| to be traveling in the direction of the arrow (Fig. 4), this movement continues until the table dog 332a engages the dog lever 340 and rocks the lever in a clockwise direction' until the stud or screw `344` is engaged by the stud 342, and further movement rocks the control lever 333 in ancounterclockwise direction, which serves to rock the lever 331 into substantially the position shown in Fig. 4, which movement shifts the valve stem |22 slightly toward the right (Fig. 3) so that fluid under pressure is cut off from both the pipe ||9 and the pipe |20, thus stopping the table 2| in the desired position for grinding the next cam on the camshaft.

The dog lever 340 is pivotally supported on the stud 34| and is arranged to swing in a direction The dog lever 340 is provided with an integral hub portion 350 which is arranged so that it may be moved longitudinally on the pin or stud 34| so as to throw the dog lever 340 out of the path of the table dogs 3320.. In the preferred form a mechanism is provided for automatically throwing the dog lever 340 out of engagement with the table dog 33 2a in timed relation with the other movements of the table. A rock arm 35| is pivotally ytothe base of the machine.

Supported on a'stud 352 which is fixed relative The upper end of the lever 35| is formed as a yoke-shaped member having a pair of diametrically opposed pins 334 and 355 which engage apertures within the sleeve 353 so that when the lever 35| is rocked in a clockwise direction about its supporting stud 352, the hub 353 will be moved toward the right (Fig. and the dog lever 35.13 will be moved out of the path of the table stop dog 3320., which serves to release the spring-pressed plunger 349, and the roller 333 rocks the cam 33T and thelever 331 in a clockwise direction (Figs. 3 Vand 4) to move the Valve |2| into the position illustrated in Fig. 3 so that the pipe |20 is uncovered to allow passage of fluid to the cylinder chamber H3.

It is desirable that the dog lever 333 be thrown out of engagement ,withy the table stop dogs 332s yin timed relation with the other parts of the machine. This is preferably accomplished by means of a uid pressure actuated mechanism comn prising a cylinder 363 having a piston 36| slidably kmounted therein. A piston rod 362 is connected to move with the piston 36| and an adjustable screw 363 carried in the forward end of the piston rod V362 is arranged to engage the lower end of the lever 35|. A spring 334 normally holds the piston 36| in a right-hand position (Fig. 5) so that the stop lever 343 is in the path of the table stop dogs 332er. A spring 365 (Fig. e) which is interposed between a projecting lug 336 on the lever 35| and a portion of thebase 2| serves to hold the lever 35| in the position shown in Fig. 5. When fluid under pressure is armitted through a pipe 367 into a cylinder chamber 363, the spring 365; is compressed and the lever 35| rocked in a clockwise direction (Fig. '5) to move the dog lever 346 toward the right out of the path of the table dogs 332er. The pipe 36'| is connected with the valve chamber 253 of the `rnaincontrol valve 223 so that in the position of the main control valve shown in Fig. 3, fluid will be admitted to remove the table stop lever 34D from the path of the table dogs 332m.

'The cycle control mechanism 333 above described is operative only during the infeeding or grinding cycle and is preferably arranged so that it is automatically rendered inoperative during the table traversing movement. This is preferably accomplished by providing a control valve which is actuated by movement of the table control lever so as to control the admission of fluid to a vcylinder 33). yIn the preferred forni of this invention, the spring-pressed plunger 349 is lformed as a control valve for thecycle control mechanism. The plunger 339 is slidably mounted within a casing or cylinder 3'53 which is supported on the rock shaft 334|. An upwardly extending lug 37| is held between two opposed adjusting screws 312 (only one of which has 'been shown in Fig. 5). rIhe opposed adjusting screws 372 serve to adjust the position of the cylinder or casing 316 so that the valve and the roller 333 may be adjusted relative to the cam surface 3M in setting up the mechanism.

The plunger 333y is provided with a pair of valve the fluid within the cylinder chamber 332fto vexhaust andthereby lrelease the tension yof 4the spring 3H (Fig. 12) which rocks the holding pawl 363 into an operative position in 'engage-- ment with the ratchet 36| to start actuationof the cycle control mechanism.`

Whenfthe valve 12| is'thrown into a reverse position or is shifted to stop the table movement, j

the roller 338 actuatedl by the cam surface-3411iA causes the spring-pressed plunger 336 to move upwardly,v thus admitting fluid under pressure from the pipe 336 through the pipe'3'l to the cylinder chamber r332 to hold the holding pawl 333 out of engagement with the ratchet wheel. Before the holding pawl 333 is withdrawn,` the cam 3|3 has rotated a sufficient distance to open the limit switch 3|5 which serves to break the circuit, thereby deenergizing the solenoid 2H.. and the released compression of the spring 2|6'- shifts the control valve 238 toward the right (Fig. 3) which in turn shifts the main controlvalve. v

In the position of the parts shown in Fig. 3,

when the dog lever 340 is thrown out of the` ypath of the table stop dogs 332:2, the table .3| v

the table control valve |2| during the grinding feed. This condition continues until thev 'cycley control or feed control vvalve 266 shifts into 'a' with its lower end against the stop screw 333. 'I

The lever 333 is providedrwith an inwardly projecting lug 38| which is arranged in the `path of',

the hub 353 of the dog lever 330 so as to facilitate manually throwing the dog lever 3113 out of the path of the table dogs 332e to start the operating cycle of the machine.

Wheelspindle reciprocation v -nl the preferred construction, the grinding` wheel 341 and its supporting spindle 26 are re,-

ciprocated axially through a short distan-ce dura' ing the grinding operation so as to causean'eve'n wearing of the grinding wheel face during grind` ing and to improve the quality of the vfinish produced on the cam being ground by preventing grain markings or rings around the cam `being ground. The wheel spindle reciprocating mech,-

anism has not been illustrated in detail, 'since' this is not lconsidered a part of the present invention. A wheel 4spindle reciprocating mechanism Y is contained within a portion 382 of the wheelv slide casing. Referencemay` be had to the prior U. S. patent to Belden and Silven No. `2,022,173 I for details of disclosure not contained herein. It

is desirable thatthe wheel spindle reciprocating mechanism be stopped during the truing of the grinding wheel 2 in order that a better 'finish n may be obtained on the grinding face of the f wheel. It is also desirable that the wheel'recipf.

rocation be automatically stopped in timed're-J lation with the other mechanisms of vthe machine so that when the truing 'tool is moved into operative engagement with the wheel, the wheel,

will be held against reciprocatory movement. A

pipe 363 passes fluid under pressure to a Avalve chamber v331i -located between the valve 'pistons"35i,

yet

:sa and 264 in the slow speed valve 26o. when the slow speed valve 260 is shifted toward theV right (Fig. 3) to slow down the table movement fora truing operation, uid under pressure within the valve chamber 384 passes out through a pipe 385 to the wheel spindle reciprocating mechanism contained within the casing 382 automatically to stop the reciprocation of the spindie. After the truing operation has been completed, the slow speedrvalve 260 shifts back to the position shown in Fig. 3 and fluid may exhaust through the pipe 385 and a valve chamber 386 located between the valve pistons 264 and 265 and out through a pipe 381 which returns fluid to the reservoir 206, thus allowing the Wheel spindle 25 reciprocating mechanism to start functioning and reciprocate the wheel spindle 26 for a grinding operation.

In traversing from cam to cam as well as stopping at the end of the table stroke, it is desirable that the counting mechanism be rendered inoperative and that the solenoid 2|1 be deenergized so that the rock bar 60` will remain in an inoperative position to hold the cams on the camshaft out of' engagement with the `Wheel 21 when the table traverses over a comparatively long section of the shaft, such as the center bearing, and furthermore to retain the camshaft separated from the grinding wheel during the truing operation. A normally closed limit switch 390 is mounted on the front of the machine base and is connected in series with the limit switch 3|5 of the cycle control mechanism. A plurality of dogs 39| are arranged in xed positions on the dog bar and serve to open the limit switch 393 at the desired'intervalsv during the intermittent indexing of the table 2|. Opening the switch 390 serves to open the circuit .of the limit switch 3|5, thus deenergizing the solenoid of a relay switch 392 which serves to deenergize the solenoid 2H, and the released compression of the spring 2|6 retains the feed control-cycle pilot valve in its right-hand position (Fig. 3) to retain the feed motor |12 and the camshaft |55 in a rearmost position and prevent the camshaft 55 from moving forward into engagement with the grinding wheel21 at times when the table is traversing over a main bearing or during the truing operation. A normally closed limit switch 394 is connected to a relay switch 395 and serves to stop the Work drive motor |34 during the truing operation. A dog 39B carried by the table 2| serves to open the limit switch 394 and therebystop the work drive motor |33.

`A lever 391 is pivotally mounted on a stud 39|! which is fixed to the base. An adjustably positioned stud 399 carried at the left-hand end of the lever 391 (Figi. 4) is arranged in the path of the dogs 39! and serves when engaged by the dogs 39| to rock the lever 391 in a counterclockwise direction so that the adjustable screw 40D engages an actuating roller 40| of the limit switch 336 to open the switch. The rock arm 391 is also provided with a cam surface 402 at its other end which is arranged to be engaged by a stud 433 carried by the main control lever 333 to facilitate manual operation of they switch 399 when the main control lever is shifted to start the cycle of operation.

Operation.

The operation of this automatic cam grinding machine is readily apparent from the foregoing disclosure` Assuming the` table4 2| has stopped after the truing operation has been completed, the dog lever 340 engages the right-hand side of the table stop dog 435, which shifts the control valve 2| toward the right (Fig. 3) to hold the table 2| stationary during a loading operation. A new camshaft is mounted in position and supported for rotation on the headstock spindle 62 and footstock center 34. Assuming allv of the parts to have been previously adjusted, the cycle of operation is started by movement of the main control lever 333 in a clockwise direction (Fig. 5) which serves to throw the dog lever 349 out of the path `of the table stop dog 455. The released compression of the spring back of the plunger 349, acting through the roller 343 and the cam face 341, serves to rock the lever 331 in a clockwise direction (Fig. 3) which shifts the table control valve |2| into the position illustrated in Fig. 3 so that fluid under pressure is admitted into the cylinder chamber H8. In this position of the parts, the valve 250 is in its extreme right-hand position (Fig. 3) which serves to shift the main control valve 223 into its extreme left-hand position,v thus allowing fluid under pressure to fiow through the pipe 254, the pipe |21, into the valve chamber |28 in the table control valve |2| and through the pipe |20, into the cylinder chamber H8, to cause the table 2| to move toward the right (Figs. l and 3). When the main control valve 22|) shifts into its lefthand position, the pipe 361 is opened to the exhaust and the released compression of the spring 354 shifts the piston 36| toward the right (Figs. 3 and 5) to release the compression of the spring 365 which rocks the lever 35| in a counterclockwise direction (Fig. 5) to shift the dog lever 343 into the position illustrated in Fig. 5 in the path of the table stop dogs 33m. When the dog lever 340 engages the first table stop dog 332a, the lever 34|) is rocked in a clockwise direction (Fig. 4) until the stud 342 engages the screw 344 to rock the lever 336 and main control lever 333 so as to rock the shaft 334 in a counter-clock- Wise direction and the lever 331 in a counterclockwise direction (Fig. 4) so as to shift the table control valve |2| toward the right (Fig. 3) to cut olf luidunder pressure from both .ends of the table cylinder H0.

During the shifting movement of the lever 331 in a counterclockvvise direction, the cam 341 forces the roller 348 upward against the compression .'of the spring contained within the plunger 349 which serves to shift the valve piston 314 so as to uncover the port at the end of the pressure pipe line 313 to admit fluid under pressure to the `valve chamber 315 which is also conn'ected with the pipe line 311 to pass fluid under pressure to the cylinder within the casing 323 to rock the holding pawl 331 from operative engagementwith the ratchet wheel 30|, thereby releasing the tension of the spring 32 which resets the counting mechanism and returns the limit switch 3|5 to a closed position so as to close a circuit. thereby energizing the solenoid 291 to shift the feed lcontrol-cycle pilot valve 239 into the position 

